Two More Bombshells For Vitamin D: It Prevents Both Type I Diabetes and Cavities

New reviews of existing studies as well as a recent long-term analysis are showing strong correlations between vitamin D and the reduced incidence of both type I diabetes and dental caries.

A recent article we published detailed how researchers at McGill University have discovered a molecular basis for the cancer preventive effects of vitamin D, whereby its active form essentially shuts down cancer cells.

Now two more bombshells on the beneficial effects of vitamin D.

Type I Diabetes Prevention

First,
a recent study published in Diabetologia found a correlation between serum levels of vitamin D3 and subsequent incidence of Type 1 diabetes. They found that deficiency in vitamin D may be associated with an increased risk of developing type 1 diabetes, according to new research.

Led by Dr Cedric Garland and colleagues from the University of California, San Diego, USA, the team performed a six year analysis of nearly 2,000 people -- finding that higher levels of serum vitamin D3, known as 25-hydroxyvitamin D [25(OH)D], are associated with a lower incidence of the disease.

Therefore a preventative role for vitamin D is suggested, they said --

First Time Dose-Response Relationship Tested

"Previous studies proposed the existence of an association between vitamin D deficiency and risk of and Type 1 diabetes, but this is the first time that the theory has been tested in a way that provides the dose-response relationship," said Garland.

Garland added that the data suggests a minimum level of 25(OH)D required in the blood for the prevention of around half the cases of type 1 diabetes is 50 nanograms per mililetre (ng/ml).

"While there are a few conditions that influence vitamin D metabolism, for most people, 4000 IU per day of vitamin D3 will be needed to achieve the effective levels," Garland suggested.

Study details

The study used samples from of blood serum specimens frozen by the Department of Defense Serum Registry for disease surveillance.

Garland and his team analysed 1000 samples of serum from healthy people who later developed type 1 diabetes and 1000 healthy controls whose blood was sampled on or near the same date but who did not develop type 1 diabetes.

By comparing the serum concentrations of 25(OH)D the team were able to determine the optimal serum level needed to lower an individual's risk of developing type 1 diabetes.

"The risk of insulin-requiring diabetes was 3.5 times higher in individuals with the lowest 25(OH)D concentration compared with those with the highest," reported the authors.

"Individuals in this study who had serum levels of 25 (OH)D greater than 100 nmol/l had a 70% lower risk of developing insulindependent diabetes than those with levels below 43 nmol/l," they added.

Based on these results, Garland estimates that the level of serum 25(OH)D needed to prevent half the cases of type 1 diabetes is 50 ng/ml.

"This beneficial effect is present at these intakes only for vitamin D3," cautioned Garland.

"Reliance should not be placed on different forms of vitamin D and mega doses should be avoided, as most of the benefits for prevention of disease are for doses less than 10,000 IU/day," he added.

Prevents Cavities

Second, a
new review of existing studies points toward a potential role for vitamin D in helping to prevent dental caries, or tooth decay.

The review, published in the December issue of Nutrition Reviews, encompassed 24 controlled clinical trials, spanning the 1920s to the 1980s, on approximately 3,000 children in several countries. These trials showed that vitamin D was associated with an approximately 50 percent reduction in the incidence of tooth decay.

"My main goal was to summarize the clinical trial database so that we could take a fresh look at this vitamin D question," said Dr. Philippe Hujoel of the University of Washington, who conducted the review.

While vitamin D's role in supporting bone health has not been disputed, significant disagreement has historically existed over its role in preventing caries, Hujoel noted. The American Medical Association and the U.S. National Research Council concluded around 1950 that vitamin D was beneficial in managing dental caries. The American Dental Association said otherwise -- based on the same evidence. In 1989, the National Research Council, despite new evidence supporting vitamin D's caries-fighting benefits, called the issue "unresolved."

Current reviews by the Institute of Medicine, the U.S. Department of Human Health and Service and the American Dental Association draw no conclusions on the vitamin D evidence as it relates to dental caries.

"Such inconsistent conclusions by different organizations do not make much sense from an evidence-based perspective," Hujoel said. The trials he reviewed increased vitamin D levels in children through the use of supplemental UV radiation or by supplementing the children's diet with cod-liver oil or other products containing the vitamin.

The clinical trials he reviewed were conducted in the United States, Great Britain, Canada, Austria, New Zealand and Sweden. Trials were conducted in institutional settings, schools, medical and dental practices, or hospitals. The subjects were children or young adults between the ages of 2 and 16 years, with a weighted mean age of 10 years.

Hujoel's findings come as no surprise to researchers familiar with past vitamin D studies. According to Dr. Michael Hollick, professor of medicine at the Boston University Medical Center, "the findings from the University of Washington reaffirm the importance of vitamin D for dental health." He said that "children who are vitamin D deficient have poor and delayed teeth eruption and are prone to dental caries."

The vitamin D question takes on greater importance in the light of current public health trends. Vitamin D levels in many populations are decreasing while dental caries levels in young children are increasing.

"Whether this is more than just a coincidence is open to debate," Hujoel said. "In the meantime, pregnant women or young mothers can do little harm by realizing that vitamin D is essential to their offspring's health. Vitamin D does lead to teeth and bones that are better mineralized."

Hujoel has joint appointments as a professor in the University of Washington School of Dentistry's Department of Oral Health Sciences and as an adjunct professor of epidemiology in the UW School of Public Health. His research has concentrated on nutrition with a focus on low-carbohydrate diets, harmful effects of diagnostic radiation, and evidence-based methodology and applications. He has also studied the link between dental disease and systemic disease, as well as trends in disease prevalence.

The two studies lend further support to the overwhelming disease prevention powers of vitamin D.
Mae Chan holds degrees in both physiology and nutritional sciences. She is also blogger and and technology enthusiast with a passion for disseminating information about health.